Allah's greatest name.

Allah's greatest names by which when one asks, Allah gives and by which prayers are accepted.
اللَّهُمَّ إِنِّي أَسْأَلُكَ بِأَنِّي أَشْهَدُ أَنَّكَ أَنْتَ اللَّهُ لاَ إِلَهَ إِلاَّ أَنْتَ الأَحَدُ الصَّمَدُ الَّذِي لَمْ يَلِدْ وَلَمْ يُولَدْ وَلَمْ يَكُنْ لَهُ كُفُوًا أَحَدٌ
Allahumma Inni As’aluka Bi Anni Ashhadu Annaka Antalllah, La Ilaha Illa Anta Al-Ahadus-Samadu, Alladhi Lam Yalid Wa Lam Yulad, Wa Lam Yakun Lahu Kufuwan Ahad